Electric fuel pump wiring suggestions needed

[Claybuster]

Hello all,
I am in need of some suggestions on re-wiring my MkIV's electric fuel pump. I had a no start issue today, and I traced it to faulty wiring (my fault...) in the fuel pump harness. I have the Pro-M hanger with a walbro gss340 pump. When I spliced the connector from the pump into the wires on the hanger, I used some solder-type butt connectors and heat shrink tubing. The failure occurred at both butt connectors. I thought the heat shrink tubing would keep the connectors protected, but I'm pretty sure the fuel finally got to them. Obviously, I did not use fuel-rated heat shrink tubing.
For those that have wired your fuel pumps like I did, what kind of connectors and heat shrink tubing (if any?) did you use? Is there a better way to splice in the pump to enable use of the existing Ron Francis/Mustang connector on the outside of the tank? Does anybody have a suggestion for a "beefier"/heaver guage connector for the fuel pump?
As always, your thoughts are appreciated!
Jason

[edwardb]

I tested several sleeving products some time ago and most failed same as you experienced. After research, I'm using Molex Perma-Seal™ brand and they handle being immersed in the tank. Specifically, with the Pro-M hanger and Walbro pump, I used Molex 19164-0077, Perma-Seal™ Heat Shrink & Crimp Step-Down Butt Connector, 16-14/12-10 Ga. Fit the wire gauges for my build perfectly. I found them at DelCity.net. You have to buy several but don't recall they were real expensive. Maybe available elsewhere.

[Claybuster]

Thanks, Paul! Did you use any other heat shrink tubing over the connectors? Maybe they don't need it?
I appreciate your help!
Jason

[PMD24]

I researched materials for submersion in gasoline and found that most common heat shrink materials won't tolerate that application for any extended period. I was able to find heat shrink in a material that is suitable for submersion in gasoline. I will track that information down tomorrow and post it here. I'm pretty sure I have enough left over to stick some in the mail to you if that would be helpful. Will look for that tomorrow as well. Note: My car is still in the build phase so I don't have any real data on how well this actually performs. Sounds like Paul's Molex material does, so that's probably a better bet.

For my project I chose to use crimp style connectors as well, with a proper ratcheting crimper for the wire gauges involved. Getting into all of the possible combinations of solder compounds and fluxes, and their tolerance for submersion in fuel got too messy, so I abandoned that approach.

2/12/26 Update: I see you went with Paul's materials which are proven but did want to provide the follow-up I mentioned above. The heat shrink that I found that is supposed to be suitable for submersion is gasoline is Raychem Viton. I cut off a piece and put it in a jar of gas yesterday. Used gas with ethanol for the test.

[cv2065]

+1 on the Permaseal connectors. I read that Paul used them in one of his build threads and they worked great. I submerged one in fuel for a week and no issues. I tried the fuel resistant shrink and it fell apart during the same test, so I just used the Permaseal. I think the shrink was from Raychem.

[edwardb]

Thanks, Paul! Did you use any other heat shrink tubing over the connectors? Maybe they don't need it? I appreciate your help!
Jason

Just the Permaseal connectors.

https://thefactoryfiveforum.com/attachment.php?attachmentid=141193&d=1611415847

[Claybuster]

Thanks, guys! Permaseal is on order. I should have ordered them during the initial build. Duh...

Paul, I see that you didn't use the neoprene insulator between the pump and hanger. Do you have any issues with vibration noise? I noticed when I pulled my pump, the insulator didn't look like it was holding up very well to the fuel. I'm thinking of leaving it out during reassembly, like you did.

Jason

[edwardb]

Thanks, guys! Permaseal is on order. I should have ordered them during the initial build. Duh...

Paul, I see that you didn't use the neoprene insulator between the pump and hanger. Do you have any issues with vibration noise? I noticed when I pulled my pump, the insulator didn't look like it was holding up very well to the fuel. I'm thinking of leaving it out during reassembly, like you did.

Jason

I've done several pump setups exactly as pictured here. There is an insulator at the bottom of the pump, which is visible, but nothing else that I'm aware of. All ran fine without any vibration or whatever.

[Claybuster]

Perfect. I will leave mine out, then. Thanks again!

Jason